Engine device including an orientation of a fuel return line attached to a common rail

Abstract

An engine device including a common rail configured to store, at a high pressure, a fuel supplied by a fuel feed pump. The common rail includes a pressure reducing valve configured to discharge the fuel in the common rail to a fuel return pipe. The fuel return pipe extends from the pressure reducing valve to a position higher than the pressure reducing valve, and then extends to a position lower than the pressure reducing valve.

The invention claimed is: 
     
         1 . An engine device comprising:
 a cylinder head;   a crankshaft;   a common rail configured to store, at a high pressure, a fuel supplied by a fuel feed pump, wherein the fuel feed pump has a first side and a second side, wherein the second side is disposed between the first side and the common rail in a direction of a line perpendicular to a longitudinal direction of the common rail, wherein the line extends through both the cylinder head and the crankshaft; and   a fuel return pipe connected to the common rail and configured to return fuel in the common rail to the fuel feed pump,   wherein the fuel return pipe is directly connected to the fuel feed pump at a connection point that is located between the first side of the fuel feed pump and the common rail in the direction of the line.   
     
     
         2 . The engine device according to  claim 1 , further comprising:
 a common rail system that includes:
 the common rail; 
 a pressure reducing valve coupled to the common rail and having a first side configured to receive the fuel from the common rail; and 
 the fuel return pipe that is distinct from the common rail, wherein the fuel return pipe is coupled to a second side of the pressure reducing valve via a first end of the fuel return pipe such that the fuel is discharged from the common rail into the first end of the fuel return pipe. 
   
     
     
         3 . The engine device according to  claim 2 , wherein:
 a second end of the fuel return pipe is coupled to the fuel feed pump such that the fuel is discharged from the second end of the fuel return pipe into the fuel feed pump,   the fuel discharged from the common rail into the fuel return pipe is discharged exclusively into the fuel feed pump, and   the fuel return pipe extends from the first end of the fuel return pipe that is coupled to the second side of the pressure reducing valve to a position higher than the first end of the fuel return pipe, without any portion of the fuel return pipe between the first end of the fuel return pipe and the position higher than the first end of the fuel return pipe extending lower than the first end of the fuel return pipe, and then extends to a position lower than the first end of the fuel return pipe.   
     
     
         4 . The engine device according to  claim 3 , wherein:
 the fuel return pipe extends from the first end of the fuel return pipe to the position higher than the first end of the fuel return pipe such that the pressure reducing valve of the common rail sustains contact with the fuel on a fuel return pipe side of the pressure reducing valve, or   the fuel return pipe extends from the first end of the fuel return pipe to the position higher than the first end of the fuel return pipe such that fuel is maintained in a portion of the fuel return pipe between the common rail and the position higher than the first end of the fuel return pipe.   
     
     
         5 . The engine device according to  claim 3 , wherein the fuel return pipe extends from the first end of the fuel return pipe to the position higher than the first end of the fuel return pipe such that fuel is maintained in a portion of the fuel return pipe that extends from the first end of the fuel return pipe to the position higher than the first end of the fuel return pipe irrespective of a mounting angle of the common rail, a direction of connecting the fuel return pipe to the common rail, or a combination thereof. 
     
     
         6 . The engine device of according to  claim 3 , wherein the pressure reducing valve includes a sliding portion, and where the fuel return pipe extends from the first end of the fuel return pipe to the position higher such that the pressure reducing valve is soaked in fuel to suppress or reduce abrasion of the sliding portion. 
     
     
         7 . The engine device according to  claim 3 , wherein the second end of the fuel return pipe is coupled directly to the fuel feed pump via a connector, the connector interposed between the second end of the fuel return pipe and the fuel feed pump, such that the fuel is discharged from the second end of the fuel return pipe directly into the connector and thereafter into the fuel feed pump. 
     
     
         8 . The engine device according to  claim 7 , wherein a first portion of the connector is coupled to the fuel feed pump, a second portion of the connector is coupled to the fuel return pipe, and a third portion of the connector is coupled to a second pipe. 
     
     
         9 . The engine device according to  claim 7 , wherein the fuel return pipe extends continuously from the first end to the second end. 
     
     
         10 . The engine device according to  claim 2 , wherein the pressure reducing valve is positioned at an end of the common rail. 
     
     
         11 . The engine device according to  claim 2 , wherein an end of a connector is configured to be inserted into the fuel return pipe via the first end of the fuel return pipe. 
     
     
         12 . The engine device according to  claim 2 , wherein:
 the entirety of the fuel return pipe extends between the first end of the fuel return pipe and a second end of the fuel return pipe;   the first end of the fuel return pipe defines a first opening of the fuel return pipe;   the second end of the fuel return pipe defines a second opening of the fuel return pipe; and   the fuel return pipe defines a flow path between the first opening and the second opening.   
     
     
         13 . The engine device according to  claim 2 , wherein the pressure reducing valve is coupled to the common rail at a first end of the common rail, the common rail system further including:
 a second fuel return pipe that is distinct from the common rail,   wherein a first end of the second fuel return pipe is coupled to the fuel feed pump such that fuel is discharged from the fuel feed pump into the first end of the second fuel return pipe, and   wherein a second end of the second fuel return pipe is coupled to a connector coupled to the common rail at a second end of the common rail opposite the first end of the common rail such that fuel is discharged from the second end of the second fuel return pipe into the connector.   
     
     
         14 . The engine device according to  claim 13 , wherein the second end of the fuel return pipe is coupled to a first portion of a second connector, wherein the first end of the second fuel return pipe is coupled to a second portion of the second connector, and wherein the fuel feed pump is coupled to a third portion of the second connector. 
     
     
         15 . The engine device according to  claim 13 , the common rail system further including:
 a fuel feed pipe, wherein a first end of the fuel feed pipe is coupled to the fuel feed pump such that high-pressure fuel is discharged from the fuel feed pump into the first end of the fuel feed pipe, wherein a second end of the fuel feed pipe is coupled to the common rail at the second end of the common rail such that the high-pressure fuel is discharged from the second end of the fuel feed pipe into the common rail.   
     
     
         16 . The engine device according to  claim 1 , further comprising a cylinder block that is provided on a lower side of the engine device, wherein the cylinder head is provided on an upper side of the engine device. 
     
     
         17 . The engine device according to  claim 1 , wherein the fuel feed pump is connected to a fuel tank through a fuel supply pipe. 
     
     
         18 . An engine device comprising:
 a fuel feed pump;   a common rail configured to store, at a high pressure, a fuel supplied by the fuel feed pump;   a fuel feed pipe connected to the fuel feed pump and configured to supply fuel in the fuel feed pump to the common rail;   a fuel return pipe connected to the fuel feed pump at a separate connection point than the fuel feed pipe is connected and configured to return fuel in the fuel feed pump to a connector coupled to the common rail;   a second fuel return pipe connected to the common rail and configured to return fuel in the common rail to the fuel feed pump; and   a third fuel return pipe connected to the common rail and configured to return fuel in the common rail to a fuel tank.   
     
     
         19 . An engine device comprising:
 a fuel feed pump connected to a fuel tank through a fuel supply pipe;   a common rail configured to store, at a high pressure, a fuel supplied by the fuel feed pump;   a pressure reducing valve coupled to a first end of the common rail and having a first side configured to receive the fuel from the common rail;   a fuel return pipe that is distinct from the common rail and configured to return fuel in the common rail to the fuel feed pump, wherein the fuel return pipe is coupled to a second side of the pressure reducing valve via a first end of the fuel return pipe such that the fuel is discharged from the common rail into the first end of the fuel return pipe, and the fuel return pipe is connected to the fuel feed pump at a connection point that is located below the common rail without being connected to the fuel supply pipe; and   a second fuel return pipe that is distinct from the common rail, wherein a first end of the second fuel return pipe is coupled to the fuel feed pump such that fuel is discharged from the fuel feed pump into the first end of the second fuel return pipe, and wherein a second end of the second fuel return pipe is coupled to a connector coupled to the common rail at a second end of the common rail opposite the first end of the common rail such that fuel is discharged from the second end of the second fuel return pipe into the connector.